I think they've outdone Halo in every way! Except possibly with the slightly overbearing emphasis on A.D.S. (aiming down sights).
I'd like to see stats: I probably use sights 90-95% of the time (even in close quarter combat with a shotgun, oddly enough). Mainly because the hit-boxes for headshots seem rather large, making them crucial (albiet, lots of fun).
This already makes hip-firing a disadvangage as you have no magnification AND lowered sensitivity like you do with A.D.S. Add to that the fact that with A.D.S. you're basically using it standing still (versus jumping or strafing), the weapon fires more accurately, and does more damage, it worsens the case even more.
I'd like to see at least equal damage and the same accuracy from hip-firing, just minus the magnification and sensitivity, which would make me consider strafing, jumping, and being more dynamic like I was in the Halo battlefields.
Even better: Add a bit of risk vs reward for hipshooting (ie. chance to do a lot more damage with a headshot). Even as a special ability on a weapon, or a perk.
Other things that are missing:
* Proximity voice chat - make toggleable
*Ghost voice from DualShock4 speaker - make toggleable
Otherwise, well done on what looks like it will be the greatest console shooter of all time. :)

I do like the idea. It would be interesting seeing a dynamic gunplay like that. From close to mid-close range being able to accurately hip-fire (no more damage though), but for further distances ADS.
I like it.